<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
          
         <script>
                  function randomString(n)
                  {
                      var teamp=getLetters();
                   var str = "";
                   for(var i=0;i<n;i++)
                   {
                       str +=str.charAt(Math.floor(Math.random*teamp.length)) 
                   }
                     return str;
                  }
             function getLetters()
             {

              var str = "";
                 for(var i=0;i<26;i++)
                 {
                     str+=String.fromCharCode(97+i);
                 }   
                 return str;

             }     
         </script>
        
</body>
</html>